System of distribution



R. W. DAVIS SYSTEM OF DISTRIBUTION May .13 1924. 1,493,968

Filed Nov. 1 1920 25 26 v 2 Sheets-Sheet. 1

May 3 1924.

- 1,493,968 R. w. DAVIS.

SYSTEM OF DISTRIBUTQTON 2 Sheets-Sheet 2 Filed Nov. 5, 1920 Patented May13, 1924.

UNITED STATES PATENT owner. I

m w. DAVIS, 01' AIJLIS, WISCONSIN, ASSIGNOR- TO ALLIS-CHALMERS MANU-FACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF 1mm.-

WARE.

srs'rnm or ni's'rmurron.

Application filed November 15, 1920. Serial Nb. 424,058.

To all whom it may concern: I

'Be it known that RAE W. DAVIS, a citizen of the United States, residingat West Allis, in the county of Milwaukee and State of \Visconsin, hasinvented a certain new and useful Improvement in Systems ofDistribution, of-which the following is a speci-- fication.

This invention relates to systems of distribution and more particularlyto such systems involving the use of motors operating in conjunctionwith energy storing means such as flywheels. The invention is applicablein cases where the rolls of a' mill, as in a steel mill, are driven byelectric motors. In cases where the work driven by electric motorsfluctuates widely and the load sometimes rises to excessive values itbecomes desirable to provide a store of energy which maybe drawn from totake care of such excessive loads. It is clearly desirable that thestored energy shall be of considerable amount to adequately take care ofpredetermined excesses. It is a rather difiicult problem however, toeconomically design a flywheel unit which will take care of the loadexcesses frequentlyoccurring in a steel mill. It is one of the objectsof this invention to provide means whereby this problem 1s solved in aneconomical and efficient manner.

It is customary in connection with the electric drive of steel mills andthe like to utilize two or more motor units.' It is one of the objectsof this invention to provide means whereby the flywheel capacity of bothunits is made available when a load is put upon either unit. Anotherobject of the invention is the provision of a system whereby the sizeand weight of the flywheels'necessar in such an installation will bereduced.

, nother object is the provision of a system' in which the power demandsfrom an electric supply line for the units will be equalized.

Another object is the provision of a system in which the loads on themotor units will be equalized so that each unit will take some of itsenergy. Other objects will ap-' pear hereinafter as the description ofthe mvention proceeds.

The novel features of the invention will appearfrom this specificationand the accom anying drawings forming a part thereof sliowing severalembodiments of the in-.

vention, and all these novel features are inmainder of the system may,if desired, be

the same as in Fig. 1.

Referring more particularly to Fig. 1,.the invention is here shown as itmay be ap lied in connection with two-work motor unlts 1, 2 each ofwhich may be connected in a suit.- able manner to driverolls of asteelmill igs. 2, 3 and 4 are modified forms or the like. The systemfurther comprises two flywheel motor-generator sets 3, 4. The motor unit1 includes two motors 5, 6 connected in series by a conductor 25. Thismotor unit is connected in series with the generators 7, 8 of the motorenerator sets 3, 4 respectively by means of the conductors 26, 27 and28. The motor unit 2 com rises motors 9, 10 connected in series by conuctor 29. .This motor unit is connected in series with generators 11',12 of the motor generator sets 3, 4 respectively by means of conductors30, 31, 32.

The generators 7, 11 of set 3, along with a flywheel 13, are driven by amotor 14, here shown as of the wound rotor induction type. Power issupplied to motor 14 through leads 15 connected to the three hase supplyline 16. The motor 14 is provided with slip rings 17 here shown asconnected to the electrodes .18 of a liquid rheostat provided with aweir 19 of shutter type. The-operation of rheostats of this type is wellknown and need not be herein described. It may be further stated thatthe rheostat in question is shown merely by way of example, it beinunder-. stood that the resistance across the s ip rin 17 may be variedthrough any other suitab e means. The shutters ofthe weir haveassociated therewith a counter-weight 20 which is so ositioned as tonormally tend to close the s utters thereby permitting theelectrode-containing receptacle to be filled with electrolyte for thepurpose of reducing the resistance across the slip rings of the motor.The weir is operatively connected to the torque motor 21 and therelation is such that when the torque of said motor increases thecounter-weight 20 will be lifted so that the shutters of the weir areopened to a predetermined extent, thereby 1ncreasing thether descriptionof this controlis therefore necessary.

The field windings 33, 34 of the motors 5, 6 are preferably connected inseries with each other and with a rheostat 35, the circuit thus formedbeing connected to and fed from the exciter buses 36, 37, in turnconnected to the exciter 38. The field windings 39, of the motors 9, 10are in like manner connected in series with each other and with arheostat 41 and also fed from the buses 36, 37.

The field windings 42, 43 of the generators 11, 12 respectively, arepreferably connected in series with each other and with a -rheostat 44through a reversing switch 45 to the buses 36, 37. The field windings.46, 47 of the generators 7, 8 respectively are in like manner connectedin series with each other and with the rheostat 48 through a reversingswitch 49 to the buses 36, 37. It

must be understood, however, that the control means for the fieldwindings of the motors and generators may be elaborated and varied tosatisfy the particular conditions confronted and the results desired tobe obtained.

The operation of the system disclosed in Fig. 1 is as follows: Inasmuch.as the motor unit 1 is supplied b a generator on each of the sets 3, 4,any oad which is put upon said motor unit will necessarily be suppliedby power from both sets. The same is true of motor unit 2. In case thereshould be a particularly heavy draft on motor unit 1, for example, theflywheel capacity of both sets will be available. By reason of the factthat one generator on each set supplies each given motor unit there willbe an inherent tendency to equalization of the loads on the flywheelmotor generator sets because if for any reason the speed of one setshould become materially lower than that of the other the generatoroperating at the higher speed will take a greater part of the load thanthe one at the lower speed. This inherent regulation is augmented by thecontrol system for the driving motors of the motor generator sets forwhen an additional current is supplied to either one of the drivingmotors the rheostat-control tial features and connections of the motorunits 1, 2 and generators 7, 8, 11, 12 as shown 1X1 Fig. 1 will besubstantially the same when the driving motors 14, 24 are controlled asshown in Fig. 2. Parts in Fig. 2 similar to those in Fig. ,1 have beengiven the same reference numerals as far as advisable, for the sakeofclearness. The weirs 19 of the rheostats controlling the motors 14 and24 respectively are controlled by torque motors 21, 58 and fed by seriestransformers 22, 60 respectively. Each weir has a counter-weight 68associated therewith and positioned so that the weight will normallytend to open the weir. The torque motors are so related to the weirsthat upon an increase in torque the counterweight will be liftedresultin in closure of the weirs to a predetermined extent. The torquemotor 21, connected to transformers 22 by conductors 51, 52, 53, isprovided with slip rings 54, said motor being here assumed to be of thewound-rotor induction type. These slip rings are connected toresistances 55, 56, 57. What has been stated in connection with torquemotor 21 also applies .to torque motor 58 the slip rings of which are inlike manner connected to a set of three resistances. A difi'erentialrelay 61 is provided and comprises opposed coils 62,

The coil 62 is here shown as connected cally connected. Associated withthe core 64 1s a member66 provided with electrically connected contactsco-oporable with the resistances55, 56, 57. The core 65 is in likemanner provided with a member 67 having contacts co-operable with thesimilar resistances associated with the torque motor 58.

The operation of the control system disof the torque motor 58. The lossof torque in the torque motor 21 will permit the counter-weight 68 toopen the associated weir 19 to a predetermined extent thereby increasingthe resistance across the slip rings'17 and reducing the speed of motor14 so that the flywheel associated therewith will be permitted to ive upa predetermined amount of energy. The reduction of resistance in therotor circuit of torque motor 58, on the other hand, will cause anincrease of torque which acting against the counter-weight 68 will causea predetermined closure of the associated weir 19, thereby decreasingthe resistance across the slip rings of motor 24 and increasing thespeed of the latter so that it will take the increased load put upon it.

In the modification shown in Fig. 3 the motor 14 has its rheostat-weirmeans of torque motor 69 supplied through leads 72 connected to theserles transformer 60 associated with the main leads ofmotor 24. Themotor 24 on the other hand has the weir of its rheostat 73 controlled bymeans of a torque motor connected through leads 71 to the seriestransformers 22.

The operation of the system discloesd in Fig. 3 is as follows: Assuminthat the motor 24 is taking a heavy load t e current in seriestransformer 60 will cause an increase of torque in tor ue motor 69thereby causing the latter to 1i t the counter-weight 20 to open theweir to a predetermined extent thereby acting to slow down the speed ofmotor 14. The resulting reduction in current in the leads 15 will causereduction in the torque of motor 70 permitting the counter-weight 20 ofrheostat 73 to close the weir .a predetermined extent whereby the torqueand speed of motor 24 are increased to enable it to carry its load.

In the modification shown in Fig. 4 the motor 14 has its rheostatcontrolled by means of a torque motor 21 connected to the seriestransformers 22. The rheostat of motor 24 is controlled by means oftorque motor 74 connected to series transformers 60. In each instancethe counter-weight 20 of the rheo-- stat is so positioned as to normallytend to close the weir. Each torque motor isso related to its associatedweir than an in crease of torque will tend to lift the counterweightthereby opening the weir in question to a predetermined extent. in thismodification the torque motors are mechanically connected by anysuitable means as by a rod controlled by 76. As a result of thisconstruction the weirs of both rheostats must always be opened or closedthe same amount. It is c ear that if either motor 14, or 24 is loaded toa greater extent than'the other the associated torque motor willincrease its torque, but as the torque motors are mechanically connecteda load on one of the main motors will result in an o ening of the weirassociated with the un oaded main motor to an extent equal to that ofthe weir of the loaded main motor, whereby each flywheel is caused toassist in the carrying of the load.

It should be understood that it is not desired that the inventionclaimed be limited to the exact details of construction shown anddescribed herein, for obvious modifica tions will occur to a art.

It is claimed and desired to secure by Letters Patent:

1. In combination, a work motor, two induction motor-driven flywheelgenerator sets, said generators being connected in series to sup ly saidmotor, and a slip regulator for eac of said induction motors.

2. In combination, a work motor, two generators connected in series forsupplying said motor, each of said generators having a flywheelassociated therewith, and means whereby the flywheel operating at thehigher speed is caused to give up energy.

3. In combination, a work motor, a plurality of flywheel generator setsfor supplying said motor, and means whereby t e flywheel capacity of allsets is made available when said motor takes a load.

4. In combination, two flywheel generator sets, each set comprising twogenerators, a work motor sup lied by a generator on each set, anotherwor lr motor supplied by the remaining generators on sai sets, and meanswhereby the flywheel capacity of both sets is made available when eitherwhen either of said motors takes a load. 5. In combination, a workmotor, two motor-driven flywheel generator sets connected in series forsupplying said work motor, and means for regu ating the speed of one ofsaid drivin motors in accordance with the load on sai work motor.

6. In. combination, a work motor, two motor-driven flywheel eneratorsets connected in series for supp ying said work motor, and means forcausing the s eed of the driving motor running at the higher speed todrop a predetermined amount.

7. In combination, a work motor, two motor-driven flywheel enerator setsconnected in series for supp ying said work motor, and means efl'ectiveto maintain said driving motors at substantially the same relativespeed.

8. In combination, a work motor, two motor-driven flywheel generatorsets conperson skilled in the nected in series for supplying said workmotor, and means efiective to cause said driving motors to each take ashare of: the load substantially in proportion to their capacities.

9. In combination, two motor-driven fiywheel generator sets, each setcomprising two generators, at work motor supplied by a generator on eachset, another work motor supplied by the remaining generators on saidsets, and means for regulating the speed of one of said driving motorsin accordance with the load on said work motor.

10. In combination, two motor-driven flywheel generator sets, each setcomprising two generators, a work motor supplied by a generator on eachset, another work motor supplied by the remaining generators on saidsets, and means for causing the speed of the driving motor running atthe higher speed to drop a predetermined amount.

11. In combination, two motor-driven flywheel generator sets, each setcomprising two generators, awork motor supplied by a generator on eachset, another work motor supplied by the remaining generators on saidsets, and means eiiective to maintain said driving motors atsubstantially the same relative speed. I

12. in combination, two motor-driven flywheel generator sets, each' setcomprising twogenerators, a work motor supplied by a generator on eachset, another work motor su plied by the remaining generators on saidsets,-and means efiective to cause said driving motorsto each take ashare of the load substantially in proportion to their capacities.

means for equalizing the speed of said motors comprising means for.reducing the speed of the motor running at the higher speed in responseto the load on the other motor.

15. "in combination, a pair of motors, fed from the same source ofelectricity, means for equalizing the speed of said motors comprisingmeans for reducing the speed of the motor running at the higher speed inresponse to the load on the other motor.

16. in combination, a work motor, two

induction motor-driven flywheel generator sets, said generators beingconnected in seriesto supply said motor, and means including a. slipregulator for each of said induction motors for reducing the speed orthe induction motor running at the higher speed. v

17. In combinatioma plurality of work motors, a plurality of fly-wheelgenerator sets for supplying said work motors, and meanswhereby thefiy-wheel capacity of all oi said fly-wheel generator sets is madeavailable when any one or all of said work motors takes or take a load.

in testimony whereof, the signature or the inventor is afixed hereto. 7

" RAE W. DAVIS.

